2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/185535We examine the application of boundary states in computing amplitudes in off-shell open string theory. We find a straightforward generalization of boundary state which produces the correct matrix elements with on-shell closed string states.Latex, 10 pages, refs added, minor typos correctedHigh Energy Physics - Theorytext